International Halley Watch Newsletter

4800 Oak Grove A'Hearn activity amateur angle aperture apparition appeared archive Arizona State University ascending Node Astrometry Astrometry Network Astron Astronomical Bobrovnikoff brightness camera coma Comet Crommelin Comet Giacobini-Zinner Comet Halley cometary coordinate D. K. Yeomans Discipline Specialists dust tail emission ephemeris Festou Figure filters Giotto Halley Hotline Halley's Comet heliocentric heliocentric distance hemisphere IHW Newsletter images infrared Institute instruments International Halley Watch Jet Propulsion Laboratory L-SP Lead Center light curve magnitude March meteor Morris NASA Near-Nucleus Studies Niedner November nucleus observations of Comet Observatory obtained October P/Crommelin P/Halley particles Pasadena perihelion period photographs photometry plasma tail plates postperihelion predicted R. M. West radio science Rahe resolution Schmidt Sekanina solar wind Space spacecraft spectra spectrometers Spectroscopy spectrum standard star catalog Stevenson Telephone telescope Telex trial run U. S. Naval Observatory updated USA Dr vector Vega visual wavelength Wehinger Wyckoff